It is known to use electron beams for the treatment of aqueous effluents comprising organic contaminants. The decomposition of the contaminants originates from the action of reactive entities formed when the electrons penetrate the water, said reactive entities being OH°, H° or e−aq. A treatment comprising solely a treatment with an electron beam makes it possible to reduce the level of certain contaminants, indeed even to completely eliminate said contaminant, provided that the energy applied is sufficient in view of the contaminant concerned. However, this energy is insufficient in the majority of cases.
The basic principle of an accelerator generating an electron beam is the transfer of energy (generally of 0.5 to 10 MeV) to charged particles under the effect of an electric field created by an electrical voltage. An electron accelerator thus comprises:                a source of electrons (heated metal cathode),        one or more sources of high voltage (a series of electrodes brought to appropriate potentials),        a high-vacuum accelerating tube,        a system for focusing and then sweeping the beam for homogeneous emission,        a window (thin titanium sheet) which provides leak-tightness while allowing the accelerated electrons to pass.        
Improvements have been proposed in order to broaden the process for treatment by an electron beam to varied contaminants and/or to obtain better levels of decomposition, the improvements generally consisting in adding additives to the medium to be treated or in combining the treatment by an electron beam with another treatment.
The proposal has been made to carry out the treatment by irradiation in the presence of ozone in the reaction medium, in particular for the treatment of natural water comprising halogenated aromatic hydrocarbons, of natural water comprising halogenated alkanes and alkenes, and drinking water comprising halogenated alkanes and alkenes [Gehringer P. et al., Environmental Applications of Ionizing Radiation, edited by Cooper W. J., Curry R. D. and O'Shea K. E., Wiley and Sons Pub., (1988) pp. 325-340]; for the treatment of river water having a COD [Pikaev A. K. et al., Radiation Physics and Chemistry, (1996) 48, 75-80]; for the treatment of waste water having a COD [Pikaev et al., High Energy Chemistry, (2000b) 34, 55-73].
The addition of O3/O2 during an irradiation treatment has been employed for the treatment of synthetic water comprising halogenated aromatic hydrocarbons [Getoff, Radiation Physics and Chemistry, (2002) 65, 437-446].
The addition of active charcoal during an irradiation treatment has been described for the treatment of synthetic water comprising halogenated aromatic hydrocarbons [Dickson et al., Rapport de Atomic Energy of Canada Ltd., Pinawa MB Canada (1988) AECL 9558, 46p].
The addition of O3, H2O2, O2 and N2O has been employed for the treatment of natural water comprising halogenated alkanes or alkenes [Pikaev A. K., High Energy Chemistry, (2000a) 34, 1-12], [Pikaev A. K., Radiation Physics and Chemistry, (2002) 65, 515-526] and [Gehringer et al., Radiation Physics and Chemistry, (2002) 65, 379-386].
The addition of TiO2 has been applied to the treatment of synthetic water comprising aromatic compounds [Chitose N. et al., Chemosphere, (2003) 50, 1007-1013].
The combination with a biological treatment has been employed for the treatment of the Total Organic Carbon (TOC) of waste water and of waste water comprising BOD (biochemical oxygen demand) [Han et al., Radiation Physics and Chemistry, (2002) 64, 53-59].
The combination with a coagulation has been described for the treatment of industrial effluents comprising a COD (chemical oxygen demand) and of industrial effluents comprising a colorant [Pikaev A. K., High Energy Chemistry, (2000b) 34, 55-73].
The combination with a coagulation, a flocculation and a biological treatment has been described for the treatment of industrial effluents comprising a COD and of industrial effluents comprising a colorant [Shin et al., Radiation Physics and Chemistry, (2002) 65, 539-547].
A process which combines an adsorption on a plant material with an irradiation has been described for the treatment of spring water comprising metals [Pikaev, 2000b, mentioned above].
A process in which an Fe(II) salt is added to the effluent subjected to an irradiation is described for the removal of organic dye molecules present in dyeing effluents [C. N. Kurucz et al., J. Adv. Oxid. Technol., Vol. 3, No. 1, 1998, pp. 116-123].
The majority of these processes of the prior art, which combine a treatment by an electron beam and an additional treatment, have improved performances in reducing the content of contaminant. However, they exhibit several disadvantages. Some combinations involve expensive reactants or else their use may be problematic (in particular when there is transfer of ozone or the need to recover solid catalysts). The combination with other treatment processes is cumbersome and often results in a significant expense. Finally, the improvement is not always sufficient.